A set of 50 photographs and associated handwritten descriptive notes, acquired from the Imperial Russian Geographical Society in St. Petersburg. The complete notes, "1904 View of Great Tibet", are available at: http://collections.lib.uwm.edu/u?/tibet,94

Potala from SSW. [Z.]
This view has been taken by Ts'ibikov [Tsybikoff] during the festival he calls Ts'og Ch'od (1) [Tsog Chod] celebrated on the 29th day of the second moon of the Tibetan year (18/5 April 1901). The huge pictures hang on the palace wall beneath the Nam-gyal Ch'oide [Namgyal Ch-oide], the monastery of the palace represent Jakya Muhi [Sakya-Muni] (on the right one) and Tara or Doma (on the left). Crowds of people cover the slope of the hill and stand at the foot of the picture.
Obs. 1) Sung ch'o Rockhill l.c. p. 8 footnote.

"In the first moon of the year the lamas of Potala, as well as all those from the various temples and convents of Lhasa, and those from Anterior and Ulterior Tibet, amounting in all several myriads, assemble at the Jok'ang to read the sacred books for twenty days. In the second moon of the year there is another gathering for the same purpose at the Jok'ang, lasting eight days (1). […])
(1) This feast is called Sung ch'o (gsung ch's) in Tibetan. (p.8)
Rockhill, W.W. (1890). Tibet: A geographical, ethnographical, and historical sketch derived from Chinese sources. London: Royal Asiatic Society.